Peterborough United, who also boasted maximum points going into this afternoon's clash with Crawley Town, were dealt a shock defeat to Richie Barker's men, with Gary Alexander striking in either half to down Posh.
Kickoff was preceded by the news of Bakary Sako's omission from the Wolves squad amid interest from Nottingham Forest, but the West Midlands outfit put off-the-pitch matters to one side by producing a superb second-half performance to dispatch the Valiants.
Elsewhere in League One, Coventry City, who began the season with a 10-point deduction, spurned the opportunity to kick-start their season by earning a neutral points-tally after being held to a 1-1 draw with Shrewsbury Town.
Tranmere Rovers bounced back from their demoralising 5-0 defeat to Peterborough last week with a 1-0 victory over Oldham Athletic, as Ryan Lowe's 90th-minute strike proved sufficient for them to pick up their first victory of the campaign.
Results in full: Brentford 0-0 Carlisle United, Colchester United 1-2 Leyton Orient, Gillingham 1-1 Bristol City, Notts County 0-1 Rotherham United, Oldham Athletic 0-1 Tranmere Rovers, Peterborough United 0-2 Crawley Town, Port Vale 1-3 Wolverhampton Wanderers, Sheffield United 0-1 MK Dons, Shrewsbury Town 1-1 Coventry City, Stevenage 1-1 Bradford City, Swindon Town 5-0 Crewe Alexandra, Walsall 0-3 Preston North End.